CC (midterms) Flashcards
Enzymes
Biologic proteins that catalyze the biochemical reactions
Intracellular proteins to hasten the chemical reaction
Affects the reaction of organic matter
Enzymes are not consumed nor altered
Only the substrates changes the form (substrate to product)
Increased enzymes in the serum may be because:
Cell injury or cell degradation
Increased membrane permeability allowing for proteins to move out of the cell
Function of enzymes:
Hydration of carbon dioxide during respiration
Nerve induction
Muscle contraction
Nutrient degradation
Growth and reproduction
Energy storage and use
LIVER ENZYMES
Aspartate aminotransferase (AST)
Alanine aminotransferase (ALT)
Gamma-Glutamyl transferase (GGT)
Alkaline phosphatase (ALP)
Acid phosphatase (ACP)
MI Profile
Creatine Kinase (CK)
Aspartate Aminotransferase (AST)
Lactate Dehydrogenase (LDH)
Pancreatic Enzymes
Amylase (AMS)
Lipase (LPS)
Prostate enzymes
Acid phosphatase (ACP)
Glucose-6-phosphate dehydrogenase (G6PDH)
Miscellaneous enzymes
- 5’ Nucleotidase (5’N)
- Cholinesterase / Pseudocholinesterase
- Angiotensin-Converting enzyme (ACE)
- Ceruloplasmin
- Ornithine carbamoyl Transferase (OCT)
- Glucose-6-phosphate dehydrogenase (G-6PD)
other name for AST
Serum glutamic-oxaloacetic transaminase or Serum glutamate-oxaloacetate transaminase (SGOT)
Transfer of an amino group between aspartate and a-keto acids
AST
Involved in the synthesis and degradation of AA (amino acids)
AST
Widely distributed, highest activities in cardiac, liver and skeletal muscle
AST
2 isoenzymes of AST
Cytoplasmic
Mitochondrial
most abundant, the most predominant AST in healthy human serum
Cytoplasmic AST
present in the mitochondrial membrane. An increase in this isoenzyme indicates possible necrosis or severe damage of the cell.
Mitochondrial AST
After MI, AST levels begin to rise in ___, peak at ___, and return to normal in ____.
6–8 hours; 24 hours; 5 days
AST increased in
in hepatocellular and skeletal muscle disease
Uses malate dehydrogenase and monitors decrease in absorbance at 340 nm
Karmen Method
method that is falsely ↑ in hemolyzed sample
Karmen Method
Karmen Method reference range:
5-30 U/L
Aspartic acid + a-ketoglutaric acid ⇆ ____________
glutamic acid + oxaloacetic acid
oxaloacetate + NADH + H ⇆ _____
malate + NAD
are enzymes with similar catalytic activity but differ in the physical, biochemical and immunologic properties.
Isoenzymes
a type of cofactor that serves as the second substrate for enzymes.
Coenzymes
When a coenzyme is tightly bound to an enzyme, it is called a ____
prosthetic group
Oxidized form: NAD measures for
Decreased absorbance
Reduced form: NADH
high/increased absorbance
other name for Alanine aminotransferase (ALT)
serum glutamic-pyruvic transaminase (SGPT)
Transfer of an amino group between alanine and a-ketoglutarate
ALT
more liver specific compared to AST
ALT
Increased in hepatocellular disorders
ALT
Significant in the evaluation of hepatic disorders
Markedly increased in acute inflammatory conditions of the liver
Used to monitor the course of hepatitis treatment and the effects drug therapy
Used for screening for post transfusion hepatitis
Used to screen blood donors, (ALT increased with people with jaundice)
Used as sensitive test for occupational toxic exposure
Monitors course of hepa treatment and possible effects of drug therapy
uses of ALT
The AST/ALT Ratio
Differentiates the cause of hepatic disorder
De Ritis Ratio
Ratio > 1
non viral origin
Ratio < 1
viral in origin
pyruvate + NADH + H ⇆ _____
Lactate + NAD
pyruvate +glutamate ⇆ _____
alanine + a-ketoglutarate
Assay for enzyme activity ALT
Uses Lactate Dehydrogenase and monitors decrease in absorbance at ___
340 nm
COLOR DEVELOPER ALT and AST
2,4 DNPH
COLOR INTENSIFIER ALT & AST
0.4 N NaOH
METHODS for ALT and AST
Reitman and Frankel
Catalyze the transfer of the y-glutamyl residue from y-glutamyl peptides to amino acids H2O, etc
Gamma-Glutamyl transferase (GGT)
In the biologic system, the common donor for y-glutamyl is _____
glutathione
glutathione + amino acid → ___
glutamyl-peptide + L-cysteinyglycine
Used for diagnosis hepatobiliary disorders and chronic alcoholism
GGT
GGT is located in the ____ of the hepatic cells. Specifically in the epithelial cell linings of _____
canaliculi; biliary ductules
Sensitive marker for ethanol intoxication.
Marker for occult alcoholism
GGT
Most sensitive marker for acute alcoholic hepatitis
GGT
Assay for Enzyme Activity in GGT
Szaz Assay
The absorbance of p-Nitroaniline is measured at
405-420 nm
y-glutamyl-p-nitroanilide + glycylglycine → ____
y-glutamyl-glycylglycine + p-nitroaniline
Involved in the storage of high-energy creatine phosphate in muscle cells
Creatine Kinase (CK) or Creatine Phosphokinase (CPK)
CK is widely distributed, highest activities in _____.
skeletal muscle, heart and brain.
creatine phosphate + ADP → ___
creatine + ATP
Methods of determination for CK
Forward Reaction (Tanzer-Gilvarg)
Reverse Reaction (Oliver-Rosalki)
Optimum pH for Tanzer Gilvarg
9.0
Optimum pH for Oliver-Rosalki
6.8
↓ in absorbance at 340 nm is determined
Forward Reaction (Tanzer-Gilvarg)
↑ in absorbance at 340 nm is determined
Reverse Reaction (Oliver-Rosalki)
Source of Error for CK
Hemolysis
inactivation by light
Physical activity and IM injections
Reference Range of CK (male & female; % of CK-MB)
Male: 15-160 U/L; Female: 15-130 U/L
CK-MB: <6% of total CK
Slowest mobility toward the anode
Major isoenzyme in striated muscle and normal serum
Ck-3/CK-MM/
Muscle type
2nd fastest to migrate toward the anode
Significant quantities are found in heart tissues
CK-2/CK-MB/
Hybrid type
Migrate the fastest toward the anode
Highest concentration in CNS, GI tract and uterus (pregnancy)
CK-1/CK-BB/
Brain type
After MI, CK-MB (>6%) levels begin to rise within ___, peak at ____ and return to normal levels within ___
4-8 hours; 12-24 hrs; 48-72 hrs
It is the first enzyme to elevate after a myocardial infarction
CK
CK is considered a ____ . It is composed of two different monomers. Composed of M and B type
dimeric molecule
Reference Values of CKs
CK-MM: 94-98%
CK-MB: 2-6%
CK-BB: <1%
Other CK Isoenzymes
Macro-CK
CK-BB is complexed with antibodies __
IgG or IgA
CK-MM is complexed with ___
lipoproteins
macro-CK migrate midway between ___
CK-MM and CK-MB
Located in mitochondrial membrane, increase in this indicates cell necrosis or severe damage
Migrates cathodal to CK-MM
Mitochondrial CK (CK-Mi)
Where the activity of CK1, CK2 and CK3 are all measured
It is less diagnostic bc it is not tissue specific
Total CK